Treat empty JWK Set URI as absent

Signed-off-by: Vinod Kumar <codingkiddo@gmail.com>

See gh-50755

module/spring-boot-security-oauth2-resource-server/src/main/java/org/springframework/boot/security/oauth2/server/resource/autoconfigure/JwkSetUriCondition.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2012-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.security.oauth2.server.resource.autoconfigure;
+
+import org.springframework.boot.autoconfigure.condition.ConditionMessage;
+import org.springframework.boot.autoconfigure.condition.ConditionOutcome;
+import org.springframework.boot.autoconfigure.condition.SpringBootCondition;
+import org.springframework.context.annotation.ConditionContext;
+import org.springframework.core.env.Environment;
+import org.springframework.core.type.AnnotatedTypeMetadata;
+import org.springframework.util.StringUtils;
+
+/**
+ * Condition for creating a JWT decoder using a JWK Set URI.
+ *
+ * @author Vinod Kumar M
+ */
+class JwkSetUriCondition extends SpringBootCondition {
+
+	@Override
+	public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) {
+		ConditionMessage.Builder message = ConditionMessage.forCondition("JWK Set URI Condition");
+		Environment environment = context.getEnvironment();
+		String jwkSetUri = environment.getProperty("spring.security.oauth2.resourceserver.jwt.jwk-set-uri");
+		if (!StringUtils.hasText(jwkSetUri)) {
+			return ConditionOutcome.noMatch(message.didNotFind("jwk-set-uri property").atAll());
+		}
+		return ConditionOutcome.match(message.foundExactly("jwk-set-uri property"));
+	}
+
+}

module/spring-boot-security-oauth2-resource-server/src/test/java/org/springframework/boot/security/oauth2/server/resource/autoconfigure/servlet/OAuth2ResourceServerAutoConfigurationTests.java

@@ -362,6 +362,18 @@ class OAuth2ResourceServerAutoConfigurationTests {
 				assertThat(context.containsBean("jwtDecoderByIssuerUri")).isFalse();
 			});
 	}
+	
+	@Test
+	void autoConfigurationWhenIssuerUriPresentAndJwkSetUriEmptyShouldUseIssuerUri() {
+		this.contextRunner
+			.withPropertyValues("spring.security.oauth2.resourceserver.jwt.issuer-uri=https://issuer-uri.com",
+					"spring.security.oauth2.resourceserver.jwt.jwk-set-uri=")
+			.run((context) -> {
+				assertThat(context).hasSingleBean(JwtDecoder.class);
+				assertThat(context.containsBean("jwtDecoderByJwkKeySetUri")).isFalse();
+				assertThat(context.containsBean("jwtDecoderByIssuerUri")).isTrue();
+			});
+	}
 
 	@Test
 	void autoConfigurationWhenKeyLocationAndIssuerUriPresentShouldUseIssuerUri() throws Exception {